Create NodeAgentContextManager

3 files changed, 116 insertions, 0 deletions

diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentContextManager.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentContextManager.java
new file mode 100644
index 00000000000..245652ed927
--- /dev/null
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentContextManager.java
@@ -0,0 +1,77 @@
+// Copyright 2019 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.node.admin.nodeagent;
+
+import java.util.Objects;
+
+/**
+ * @author freva
+ */
+public class NodeAgentContextManager implements NodeAgentContextSupplier, NodeAgentScheduler {
+    private final Object monitor = new Object();
+    private NodeAgentContext currentContext;
+    private NodeAgentContext nextContext;
+    private boolean wantFrozen = false;
+    private boolean isFrozen = true;
+    private boolean pendingInterrupt = false;
+
+    public NodeAgentContextManager(NodeAgentContext context) {
+        currentContext = context;
+    }
+
+    @Override
+    public void scheduleTickWith(NodeAgentContext context) {
+        synchronized (monitor) {
+            nextContext = Objects.requireNonNull(context);
+            monitor.notifyAll();
+        }
+    }
+
+    @Override
+    public boolean setFrozen(boolean frozen) {
+        synchronized (monitor) {
+            if (wantFrozen != frozen) {
+                wantFrozen = frozen;
+                monitor.notifyAll();
+            }
+
+            return isFrozen == frozen;
+        }
+    }
+
+    @Override
+    public NodeAgentContext nextContext() throws InterruptedException {
+        synchronized (monitor) {
+            isFrozen = true;
+            while (nextContext == null) {
+                if (pendingInterrupt) {
+                    pendingInterrupt = false;
+                    throw new InterruptedException("interrupt() was called before next context was scheduled");
+                }
+
+                try {
+                    monitor.wait();
+                } catch (InterruptedException ignored) { }
+            }
+            isFrozen = false;
+
+            currentContext = nextContext;
+            nextContext = null;
+            return currentContext;
+        }
+    }
+
+    @Override
+    public NodeAgentContext currentContext() {
+        synchronized (monitor) {
+            return currentContext;
+        }
+    }
+
+    @Override
+    public void interrupt() {
+        synchronized (monitor) {
+            pendingInterrupt = true;
+            monitor.notifyAll();
+        }
+    }
+}
\ No newline at end of file
diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentContextSupplier.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentContextSupplier.java
new file mode 100644
index 00000000000..1fc730a3cb0
--- /dev/null
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentContextSupplier.java
@@ -0,0 +1,21 @@
+// Copyright 2019 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.node.admin.nodeagent;
+
+/**
+ * @author freva
+ */
+public interface NodeAgentContextSupplier {
+
+    /**
+     * Blocks until the next context is ready
+     * @return context
+     * @throws InterruptedException if {@link #interrupt()} was called before this method returned
+     */
+    NodeAgentContext nextContext() throws InterruptedException;
+
+    /** @return the last context returned by {@link #nextContext()} or a default value */
+    NodeAgentContext currentContext();
+
+    /** Interrupts the thread(s) currently waiting in {@link #nextContext()} */
+    void interrupt();
+}
diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentScheduler.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentScheduler.java
new file mode 100644
index 00000000000..3806c3d6bf3
--- /dev/null
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/nodeagent/NodeAgentScheduler.java
@@ -0,0 +1,18 @@
+// Copyright 2019 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.node.admin.nodeagent;
+
+/**
+ * @author freva
+ */
+public interface NodeAgentScheduler {
+
+    /** Schedule a tick for NodeAgent to run with the given NodeAgentContext */
+     void scheduleTickWith(NodeAgentContext context);
+
+    /**
+     * Will eventually freeze/unfreeze the node agent
+     * @param frozen whether node agent should be frozen
+     * @return True if node agent has converged to the desired state
+     */
+    boolean setFrozen(boolean frozen);
+}